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2015-10-23i2c: imx: implement bus recoveryGao Pan
Implement bus recovery methods for i2c-imx so we can recover from situations where SCL/SDA are stuck low. Once i2c bus SCL/SDA are stuck low during transfer, config the i2c pinctrl to gpio mode by calling pinctrl sleep set function, and then use GPIO to emulate the i2c protocol to send nine dummy clock to recover i2c device. After recovery, set i2c pinctrl to default group setting. Signed-off-by: Fugang Duan <B38611@freescale.com> Signed-off-by: Gao Pan <b54642@freescale.com> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-23at24: enable ACPI device found on Galileo Gen2Andy Shevchenko
There is a 24c08 chip connected to i2c bus on Intel Galileo Gen2 board. Enable it via ACPI ID INT3499. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-23mfd: intel_quark_i2c_gpio: support devices behind i2c busAndy Shevchenko
On Intel Galileo Gen2 the GPIO expanders are connected to the i2c bus. For those devices the ACPI table has specific parameters that refer to an actual i2c host controller. Since MFD now copes with that specific configuration we have to provide a necessary information how to distinguish devices in ACPI namespace. Here the _ADR values are provided. Acked-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-23mfd: intel_quark_i2c_gpio: load gpio driver firstAndy Shevchenko
On Intel Galileo boards the GPIO expander is connected to i2c bus. Moreover it is able to generate interrupt, but interrupt line is connected to GPIO. That's why we have to have GPIO driver in place when we will probe i2c host with device connected to it. Acked-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-23mfd: core: redo ACPI matching of the children devicesAndy Shevchenko
There is at least one board on the market, i.e. Intel Galileo Gen2, that uses _ADR to distinguish the devices under one actual device. Due to this we have to improve the quirk in the MFD core to handle that board. Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-23i2c: uniphier_f: add UniPhier FIFO-builtin I2C driverMasahiro Yamada
Add support for on-chip I2C controller used on newer UniPhier SoCs such as PH1-Pro4, PH1-Pro5, etc. This adapter is equipped with 8-depth TX/RX FIFOs. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-23i2c: uniphier: add UniPhier FIFO-less I2C driverMasahiro Yamada
Add support for on-chip I2C controller used on old UniPhier SoCs such as PH1-LD4, PH1-sLD8, etc. This adapter is so simple that it has no FIFO in it. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-23i2c: designware: reverts "i2c: designware: Add support for AMD I2C controller"Ken Xue
The patch reverts commit a445900c9060 (i2c: designware: Add support for AMD I2C controller). It never worked anyhow because it did not register a proper clkdev. Since kernel 4.1 starts to support APD, there is no need to get freq from id->driver_data for AMD0010. clkdev is supposed to be already registered in APD. So, revert old design and make AMD0010 looks like other ones. Signed-off-by: Ken Xue <Ken.Xue@amd.com> Signed-off-by: Xiangliang Yu <Xiangliang.Yu@amd.com> Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-23i2c: imx: add support for Freescale Layerscape platformsShaohui Xie
Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com> Signed-off-by: Hou Zhiqiang <B48286@freescale.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-22i2c: at91: fix write transfers by clearing pending interrupt firstCyrille Pitchen
In some cases a NACK interrupt may be pending in the Status Register (SR) as a result of a previous transfer. However at91_do_twi_transfer() did not read the SR to clear pending interruptions before starting a new transfer. Hence a NACK interrupt rose as soon as it was enabled again at the I2C controller level, resulting in a wrong sequence of operations and strange patterns of behaviour on the I2C bus, such as a clock stretch followed by a restart of the transfer. This first issue occurred with both DMA and PIO write transfers. Also when a NACK error was detected during a PIO write transfer, the interrupt handler used to wrongly start a new transfer by writing into the Transmit Holding Register (THR). Then the I2C slave was likely to reply with a second NACK. This second issue is fixed in atmel_twi_interrupt() by handling the TXRDY status bit only if both the TXCOMP and NACK status bits are cleared. Tested with a at24 eeprom on sama5d36ek board running a linux-4.1-at91 kernel image. Adapted to linux-next. Reported-by: Peter Rosin <peda@lysator.liu.se> Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com> Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> Tested-by: Peter Rosin <peda@lysator.liu.se> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Fixes: 93563a6a71bb ("i2c: at91: fix a race condition when using the DMA controller") Cc: stable@vger.kernel.org #4.1
2015-10-22i2c: designware: Fix build error when !CONFIG_PM_SLEEPJarkko Nikula
Commit ("i2c: designware: Rename platform driver probe and PM functions") introduced "'dw_i2c_plat_prepare' undeclared here" and "'dw_i2c_plat_complete' undeclared here" build errors when CONFIG_PM_SLEEP is not set. Fix this by renaming NULL defined dw_i2c_prepare and dw_i2c_complete PM hooks to dw_i2c_plat_prepare and dw_i2c_plat_complete since this was obviously missing from the commit. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: stu300: Fix module autoload for OF platform driverLuis de Bethencourt
This platform driver has a OF device ID table but the OF module alias information is not created so module autoloading won't work. Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: rk3x: Fix module autoload for OF platform driverLuis de Bethencourt
This platform driver has a OF device ID table but the OF module alias information is not created so module autoloading won't work. Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: meson: Fix module autoload for OF platform driverLuis de Bethencourt
This platform driver has a OF device ID table but the OF module alias information is not created so module autoloading won't work. Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: ibm-iic: Fix module autoload for OF platform driverLuis de Bethencourt
This platform driver has a OF device ID table but the OF module alias information is not created so module autoloading won't work. Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: rcar: Remove obsolete platform data supportGeert Uytterhoeven
Since commit 4baadb9e05c68962 ("ARM: shmobile: r8a7778: remove obsolete setup code"), Renesas R-Car SoCs are only supported in generic DT-only ARM multi-platform builds. The driver doesn't need to use platform data anymore, hence remove platform data configuration. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> [wsa: removed now unused ret value and cast to proper enum type] Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: sh_mobile: add support for r8a7795 (R-Car H3)Wolfram Sang
Enable the I2C core for this SoC. It is compitable to Gen2 SoCs, so reuse the settings. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: rcar: add support for r8a7795 (R-Car H3)Wolfram Sang
Enable the I2C core for this SoC. I add a new type because this version has new features (e.g. DMA) which will be added somewhen later. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: ocores: support big-endian register layoutMax Filippov
This allows using OpenCores I2C controller attached to its host in native-endian mode with bi-endian CPUs. Example of such system is Xtensa XTFPGA platform. Acked-by: Peter Korsgaard <peter@korsgaard.com> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: au1550: relax bus timings a bitManuel Lauss
The i2c-au1550 driver has to program various setup and hold times for the sda/scl signals by hand. The current values seem to be working best when the driver is supplied with 50MHz, however on the DB1300 board 48MHz is the closest we can get to it, and the timings are a bit too tight for that, leading to the last bit of a transmission sometimes being swallowed. This manifests itself in wrong readings of the ne1619 sensor and inability to configure the wm8731 i2s codec. With the relaxed timings, both the sensor and the i2s codec can now be accessed more reliably over a wider range of I2C block input frequencies. Verified on DB1200, DB1300 and DB1550 boards. Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: tegra: drop duplicated code for assigning algoBarry Song
This code is repeated in probe: i2c_dev->adapter.algo = &tegra_i2c_algo; Cc: Donglin Peng <pengdonglin137@163.com> Signed-off-by: Barry Song <21cnbao@gmail.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: davinci: Optimize clock generation on Keystone SoCAlexander Sverdlin
According to "KeyStone Architecture Inter-IC Control Bus User Guide", fixed additive part of frequency divisors (referred as "d" in the code and datasheet) always equals to 6, independent of module clock prescaler. module clock frequency master clock frequency = ---------------------- (ICCL + 6) + (ICCH + 6) It was not the case with original Davinci IP. Introduce new compatible property "ti,keystone-i2c", which triggers special handling in the driver. Without this change Keystone-based systems (having 204.8MHz input clock) choose prescaler 29 (PSC=28). Using d=5 in this case leads to bus bitrate ~353kHz instead of requested 400kHz. After correction, assuming d=6 bus rate is ~392kHz. This gives ~11% transfer rate increase. Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com> Tested-by: Hemanth Guruva Reddy <hemanth.guruva_reddy@nokia.com> Tested-by: Lukasz Gemborowski <lukasz.gemborowski@nokia.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: ismt: issue a warning when fail to request MSIAndy Shevchenko
Issue the warning in all error paths when unable to register MSI or its handler. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: ismt: propagate actual error codeAndy Shevchenko
Propagate actual return code when requesting interrupt fails. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: ismt: do not duplicate msi_enabled flagAndy Shevchenko
struct pci_dev already has a flag to track if MSI is enabled or not. Use it directly. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: ismt: PCI core handles power state for usAndy Shevchenko
There is no need to repeat the work that is already done in the PCI driver core. Remove suspend and resume callbacks. Note that there is no more calls performed to enable or disable a PCI device during suspend-resume cycle. Nowadays they seems to be superfluous. Someone can read more in [1]. [1] https://www.kernel.org/doc/ols/2009/ols2009-pages-319-330.pdf Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: ismt: improve usage of devres APIAndy Shevchenko
pcim_release() will release any requested region. There is no need to duplicate this effort in the driver. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c: ismt: mark register space with __iomemAndy Shevchenko
This fixes the code to suppress sparse warnings like: drivers/i2c/busses/i2c-ismt.c:725:36: warning: incorrect type in argument 2 (different address spaces) drivers/i2c/busses/i2c-ismt.c:725:36: expected void volatile [noderef] <asn:2>*addr drivers/i2c/busses/i2c-ismt.c:725:36: got void * Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-20i2c / ACPI: Rework I2C device scanningMika Westerberg
The way we currently scan I2C devices behind an I2C host controller does not work in cases where the I2C device in question is not declared directly below the host controller ACPI node. This is perfectly legal according the ACPI 6.0 specification and some existing systems are doing this. To be able to enumerate all devices which are connected to a certain I2C host controller we need to rework the current I2C scanning routine a bit. Instead of scanning directly below the host controller we scan the whole ACPI namespace for present devices with valid I2cSerialBus() connection pointing to the host controller in question. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Tested-by: Dustin Byford <dustin@cumulusnetworks.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-15i2c: designware: Move common probe code into i2c_dw_probe()Jarkko Nikula
There is some code duplication in i2c-designware-platdrv and i2c-designware-pcidrv probe functions. What is even worse that duplication requires i2c_dw_xfer(), i2c_dw_func() and i2c_dw_isr() i2c-designware-core functions to be exported. Therefore move common code into new i2c_dw_probe() and make functions above local to i2c-designware-core. While merging the code patch does following functional changes: - I2C Adapter name will be "Synopsys DesignWare I2C adapter". Previously it was used for platform and ACPI devices but PCI device used "i2c-designware-pci". - Using device name for interrupt name. Previous it was platform device name, ACPI device name or "i2c-designware-pci". - Error code from devm_request_irq() and i2c_add_numbered_adapter() will be printed in case of error. Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-15i2c: designware: Rename platform driver probe and PM functionsJarkko Nikula
Make it easier to distinguish between i2c-designware-platdrv and i2c-designware-core functions and to be consistent with i2c-designware-pcidrv. Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-15i2c: designware: Make dw_readl() and dw_writel() staticJarkko Nikula
dw_readl() and dw_writel() are not used outside of i2c-designware-core and they are not exported so make them static and remove their forward declaration. Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-15i2c: designware: Remove unused functionsJarkko Nikula
i2c_dw_is_enabled() became unused by the commit be58eda775c8 ("i2c: designware-pci: Cleanup driver power management") and i2c_dw_enable() by the commit 3a48d1c08fe0 ("i2c: prevent spurious interrupt on Designware controllers"). Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-15i2c: designware: Disable interrupts before requesting PCI device interruptJarkko Nikula
Device must not generate interrupts before registering the interrupt handler so move i2c_dw_disable_int() before requesting it. There are no known issues with this. The code has been here since commit fe20ff5c7e9c ("i2c-designware: Add support for Designware core behind PCI devices."). Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-15i2c: designware: Remove interrupt clearing from i2c_dw_pci_probe()Jarkko Nikula
There is no need to clear interrupts in i2c_dw_pci_probe() since only place where interrupts are unmasked is i2c_dw_xfer_init() and there interrupts are always cleared after commit 2a2d95e9d6d2 ("i2c: designware: always clear interrupts before enabling them"). This allows to cleanup the code and replace i2c_dw_clear_int() in i2c_dw_xfer_init() by direct register read as there are no other callers. Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-10i2c: img-scb: verify support for requested bit rateSifan Naeem
The requested bit rate can be outside the range supported by the driver. The maximum bit rate this driver supports at the moment is 400Khz. If the requested bit rate is larger than the maximum supported by the driver, set the bitrate to the maximum supported before bitrate_khz is calculated. Maximum speed supported by the driver can be increased to 1Mhz by adding support for "fast plus mode" in the future. Fixes: commit 27bce457d588 ("i2c: img-scb: Add Imagination Technologies I2C SCB driver") Signed-off-by: Sifan Naeem <sifan.naeem@imgtec.com> Acked-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: James Hartley <james.hartley@imgtec.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-10i2c: img-scb: Clear line and interrupt status before starting a transferSifan Naeem
Clear line status and all generated interrupts from the interrupt status register before starting a transfer, as we may have unserviced interrupts from previous transfers that might be handled in the context of the new transfer. Fixes: commit 27bce457d588 ("i2c: img-scb: Add Imagination Technologies I2C SCB driver") Signed-off-by: Sifan Naeem <sifan.naeem@imgtec.com> Acked-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: James Hartley <james.hartley@imgtec.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-10i2c: img-scb: use line_status instead of i2c->line_statusSifan Naeem
i2c->line_status accumulates the line status bits that have been seen with each interrupt. As we're only interested in that bit from the current interrupt, refer to line_status (the argument to img_i2c_auto) instead of i2c->line_status. Signed-off-by: Sifan Naeem <sifan.naeem@imgtec.com> Reviewed-by: James Hartley <james.hartley@imgtec.com> Acked-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-10i2c: img-scb: fix LOW and HIGH period values for the SCL clockSifan Naeem
Currently, after determining the minimum value for the High period (TCKH) the remainder of the internal clock pulses is set as the Low period (TCKL). This causes the i2c clock duty cycle to be much less than 50%. Modify the starting position to TCKH and TCKL at 50% of the internal clock, and adjusts the TCKH and TCKL values from there should the minimum value for TCKL not be met. This results in duty cycles closer to 50%. Fixes: commit 27bce457d588 ("i2c: img-scb: Add Imagination Technologies I2C SCB driver") Signed-off-by: Sifan Naeem <sifan.naeem@imgtec.com> Acked-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: James Hartley <james.hartley@imgtec.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-10i2c: img-scb: use DIV_ROUND_UP to round divisor valuesSifan Naeem
Using % can be slow depending on the architecture. Using DIV_ROUND_UP is nicer and more efficient way to do it. Fixes: commit 27bce457d588 ("i2c: img-scb: Add Imagination Technologies I2C SCB driver") Signed-off-by: Sifan Naeem <sifan.naeem@imgtec.com> Acked-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: James Hartley <james.hartley@imgtec.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-10i2c: img-scb: do dummy writes before fifo accessSifan Naeem
Move scb_wr_rd_fence to before reading from fifo and writing to fifo to make sure the the first read/write is done after the required number of cycles. Fixes: commit 27bce457d588 ("i2c: img-scb: Add Imagination Technologies I2C SCB driver") Signed-off-by: Sifan Naeem <sifan.naeem@imgtec.com> Acked-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: James Hartley <james.hartley@imgtec.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-10i2c: img-scb: enable fencing for all versions of the ipSifan Naeem
The code to read from the master read fifo, and write to the master write fifo, checks a bit in an SCB register before every byte to ensure that the fifo is not full (write fifo) or empty (read fifo). Due to clock domain crossing inside the SCB block the updated value of this bit is only visible after 2 cycles. The scb_wr_rd_fence() function does 2 dummy writes (to the read-only revision register), and it's called before reading from or writing to the fifos to ensure that subsequent reads of the fifo status bits do not read stale values. As the 2 dummy writes are required in all versions of the ip, the version check is dropped. Fixes: commit 27bce457d588 ("i2c: img-scb: Add Imagination Technologies I2C SCB driver") Signed-off-by: Sifan Naeem <sifan.naeem@imgtec.com> Acked-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: James Hartley <james.hartley@imgtec.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-09i2c: rcar: clean up after refactoringWolfram Sang
Update the comments to match current behaviour. Shorten some comments. Update copyrights. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-09i2c: rcar: revoke START request earlyWolfram Sang
If we don't clear START generation as soon as possible, it may cause another message to be generated. To keep the race window as small as possible, we clear it right at the beginning of the interrupt. We don't need checking since we always want to stop START and STOP generation on the next occasion after we started it. This patch improves the situation but sadly does not completely fix it. It is still to be researched if we can do better given this HW design. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-09i2c: rcar: check master irqs before slave irqsWolfram Sang
Due to broken HW design, master IRQs are more timing critical, so give them precedence over slave IRQ. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-09i2c: rcar: don't issue stop when HW does it automaticallyWolfram Sang
The manual says (55.4.8.6) that HW does automatically send STOP after NACK was received. My measuerments confirm that. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-09i2c: rcar: init new messages in irqWolfram Sang
Setting up new messages was done in process context while handling a message was in interrupt context. Because of the HW design, this IP core is sensitive to timing, so the context switches were too expensive. Move this setup to interrupt context as well. In my test setup, this fixed the occasional 'data byte sent twice' issue which a number of people have seen. It also fixes to send REP_START after a read message which was wrongly send as a STOP + START sequence before. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-09i2c: rcar: refactor setup of a msgWolfram Sang
We want to reuse this function later. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-09i2c: rcar: remove spinlockWolfram Sang
We make sure to reinit the HW in the timeout case; then we know that interrupts are always disabled in the sections protected by the spinlock. Thus, we can simply remove it which is a preparation for further refactoring. While here, rename the timeout variable to time_left which is way more readable. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-10-09i2c: rcar: remove unused IOERROR stateWolfram Sang
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>